Seeing Boyfriend's Birthday Number After Breakup

Your ex-boyfriend's birthday number will not disappear from your environment just because you two broke up. It will be available to be seen as often as it was before, just like all the other numbers that are in your environment.

Because it is your ex-boyfriend's birthday number, you are more likely to remember seeing it of all the other numbers you see during the course of a day. I'm inclined to think that this is what you are asking — why you remember seeing the number.

Your ex-boyfriend's birthday number has a personal meaning. That makes the number notable. When a person sees a number and then notices it as special because it means something to them, seeing that number is much more likely to be remembered than the seeing of other numbers.

There are other things that make numbers notable. Emotional significance or unique digit arrangement are examples. Why You Start Seeing Certain Numbers Again and Again talks about that.

The most likely reason you see your ex-boyfriend's birthday number, I think, is because the birthday number has a special meaning to you.